Athletes frequently employ a drag, weight or impedance which act as a restraint and requires greater than normal efforts to overcome for strength speed and endurance training purposes. For example, weights may be strapped on the athlete's body prior to running or skating to force the exertion of greater effort to reach the athlete's normal running or skating speed or to run or skate a certain distance. Once removed, the athlete may achieve an increase in peak speed and endurance over the same distance. The selection of the appropriate weight, the distribution and attachment of weights to the body, and the formulation of training regimens is difficult. Moreover, the weights are relatively expensive, difficult to adjust, uncomfortable, and inconvenient to store and transport due to the number of sizes needed and their bulk and weight.
In recent years, speed and endurance training devices have increased in popularity with individuals and amateur and professional sports teams. A wide variety of equipment and training regimens have been devised for athletes engaged in all sports, including soccer, ice hockey, track and field, football, basketball, baseball, swimming and the like. Athletes have employed weighted skid sleds strapped by a cord to a belt and pulled while running across a natural or artificial turf field or weighted skid sleds that are pushed. One of the more recently developed and popular training regimens involves using the wind or water for resistance through the use of a strapped-on air chute during running or "sea anchor" like, water chute during swimming.
For example, U.S. Pat. No. 5,217,186 discloses a square shaped parachute sheet having a number of parachute lines or cords attached to it, the cords drawn through a cord spacing disk to avoid cord entanglement and attached to a strap worn by the athlete. Upon running, the parachute is intended to open in the wind and present a drag on the running athlete. Generally, the resistance afforded by the inflated parachute is dependent on the size and shape of the parachute and increases with the speed attained in running or skating with the inflated parachute. In a training regimen, the athlete runs or skates to a peak speed with the parachute attached and then releases the parachute, experiencing a momentary burst in speed. As this process is repeated, the athlete is able to progressively increase the peak speed and endurance attained without the parachute. Apparently, the ability to run or skate faster is first experienced and then learned in the process.
Sports parachutes of the type described in the '186 patent and marketed prior to the present invention have suffered from an inability to fine tune the resistance attained with a single parachute for athletes of varying weight and height. Moreover, in the training regimen of a single athlete, it is desired to change and increase the resistance as the athlete's performance improves. It has been necessary to stock or acquire a variety of parachute sheet sizes to accommodate a single athlete's improvement in performance.
In addition, the square parachute sheet of the '186 patent does not always catch the wind adequately to remain inflated, particularly during turns. The large number of cords are also difficult to keep from tangling, a problem addressed by the disk of the '186 patent.
Similar problems are experienced with other prior art parachute designs for use in speed training. Long lines can get tangled easily. The parachute shapes also fail to readily provide lift, and the inflated parachutes are unstable in both straight movement and on turning.